Radio apparatus and current-control device therefor



Filed Dec. 4, 1926 P. A. CHAMBERLAIN I RADIO APPARATUS AND CURRENTCONTROL DEVICE THEREFOR gm, A QN W @N M May 10, 1927.

Patented May 10, 1927.

UNITED STATES PATENT OFFICE.

PAUL A. CHAMBERLAINgOF CHICAGO, ILLINOIS, ASSIGNOR TO MOHAWK CORPORA-TION OF ILLINOIS, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS. l

RADIO APPARATUS AND CURRENT-CONTROL DEVICE THEREFOR.

Application filed December 4, 1926. Serial No. 152,682.

This invention relates to. improvements in radio apparatus, and moreparticularly to radio receiving sets, and has for its Drincipal objectto provide an improved apparatus of the class described wherein the maincontrol devices, as for example the tuning knob and the filament switch,may be conveniently and compactly arranged on the panel.

A further object of the invention is to provide a new and improved formof filament switch, as will, hereinafter more fully appear.

The invention may best be understood by reference to the accompanyingdrawing, in which- Figure 1 is a fragmentary sectional view of a tuningcondenser in mounted position on a radio panel and with a filamentswitch combined therewith, in accordance with my invention.

Figure 2 is a detail View of the filament switch at the inner end of thecondenser shaft.

Figure 3 is a plan view of the switch shown in Figure 2.

Referring now to details shown in the drawings, I have provided a tuningdevice indicated generally at 10. In the form shown, said tuning deviceconsists of a multiple unit condenser including end frame members 1111and a rotor shaft 12 having a plurality of rotor units 13-13 spacedlongitudinally thereof, each of said rotor units comprising a set ofparallel plates 14-44; adapted to be interleaved with coacting statorplates (not shown) in a well known manner. The multiple unit condenserherein illustrated, is especially adapted for use with a single controlreceiving set wherein a plurality of radio-frequency amplificationstages are employed, all being tuned by rotation of the single rotorshaft 12. It will be understood, however, that my invention may beutilized in connection with a single unitcondenser, if desired. themultiple unit shown being utilized mainly to illustrate thepossibilities of reducing the control devices of well known radio receiving sets to a minimum, and disposing these control members in the mostadvantageous relationship on the radio panel.

As shown herein, the rotor shaft 12 con-- sists of a sleeve 12 to whichthe rotor plates face of said member for holding said sleeve in variouspositions of adjustment. This sleeve 17 also carries part of thefilament switch thereon, as will hereinafter more fully appear.

Control means for the condenser rotor shaft 12 comprises a disk or dial20 mounted on the outer end of sleeve 15 and suitably secured thereto asby means of a set screw 21. In the form shown, the dial 20 is mounted ina recess 22 formed in a panel.

23. The usual dial markings are provided on the outer face 24 of thedial 20 and are visible through an aperture 2:) formed in an escutcheonplate 26 which is mounted on the outer front side of the panel 23 andforms a'cover for the aperture 22 in which the dial 20 is mounted. Thedial is controlled by means of a knob 29 carried on a shaft 30 disposedeccentrically of the indicating dial 20. In the form shown, the shaft 30is journaled in a bearing 31 carried by the escutcheon plate 26 and isprovided with an enlarged roller portion 32 which frictionally engages aring member 33 carried on the periphery of dial 20. In the form shownherein, the friction-ring 33 is made of rubber or its equivalent. Aflexible spring 34- is mounted on the panel beneath the bearing portion32 of shaft 30 in position to maintain said bearing portion or roller infrictional engagement with the bearing ring on dial 20 It will thus beseen that very fine tuning adjustment maybe provided for the dial 20through the offset tuning knob 29.

Referring now to the switch mechanism utilized in connection with thecondenser above described, details of the switch are shown in Figures 2and 3 from which it will be seen that the sleeve member 17 at the rearend of the condenser is providedwith a supporting piece 40, preferablyof insulating material. This piece is suitably secured on the outersurface of sleeve 17, as shown in Figures 1 and 3, and forms a supportfor a pair of spring contact members 41-41 secured thereto by suitablemeans, such as rivets 4242. These spring contact members projectoutwardly or rearwardly in position to be engaged under tension by aswitch member mounted on the rear end of a shaft 45. This switch memberincludes two main paf'ts, the inner part consisting of a rectangularlyshaped metallic plate l6 and the outer part. an overlappingrectangularly shaped insulating piece 47. As seen in Figure 2, thearrangement is such that the insulating piece is wider in one directionthan the metallic piece 46 so that when the switch shaft 45 is turnedinto the position shown in this figure, the spring contacts 4l41 engageonly the sides of the insulating piece 47, and the circuit will bebroken. The metallic piece 46 has opposite sides projecting above andbelow said insulator piece as shown in this figure, however, so thatwhen the shaft 45 is turned at an angle of 90 from that shown in Figure2, the projecting margins of metallic piece 46 is then engaged with theterminal members 4141 to bridge the circuit, as shown in Figure 3. Themetallic piece 46 is preferably provided with a pair of projections ME-d6 extending from opposite corners thereof so as to limit the movementof the switch shaft to two positions, namely, on and off. The terminalcontacts 414t1 are provided with suitable conductors 48-48 connected inseries in the filament circuit (not shown) in any suitable manner so asto provide the desired control thereof. In the form shown, the condenseris of the grounded rotor type in which the rotor is electrically commonwith the end plates 11, so that it is possible to connect one of theterminal conductors 48 directly to the adjacent end plate 11, as shownin Figure 3. 1

As seen in Figure 1, the control shaft 45 extends coaxially through theentire length of the condenser shaft and has its front end 50 extendingthrough and projecting beyond the escutcheon plate 26. A control knob 51is suitably secured to this projecting end of the switch shaft 45 inposition to be readily manipulated in the usual manner.

The construction above described affords an extremely simple form ofswitch mechanism which may be incorporated as a part of the main tuningcondenser and form therewith a most compact structure capable of beingreadily assembled as a unitary structure. The-main tuning knob 29 iscarried by the escutcheon plate 26 but may also be readily assembledwith the associated tuning dial 20 of the condenser in a most simple andeconomical manner.

I claim as my invention:

1. In radio apparatus, the combination of a control panel, a rotativetuning unit including a frame and a rotor shaft, a dial for said rotorshaft visible from the exterior of said panel, a current control switchmounted on said frame including a control shaft extending eoaxiallythrough said rotor shaft. manual control means for said switch controlshaft in front of said dial, and a control knob for said rotor shaftdisposed eccentrically thereof and operatively connected with thelatter.

2. In radio apparatus, the combination of a panel, a rotative tuningunit mounted on said panel and including a frame and a rotor shaft, thelatter extending through said panel and having an indicating dialthereon, an escutcheon plate on the front of said panel having anaperture therethrough registering with the periphery of said indicatingdial, a current control switch mounted on the end of said frame oppositesaid panel including a control shaft extending coaxially through saidrotor shaft, and projecting through said escutcheon plate, a controlknob on the front end of said switch control shaft, and a control knobfor said rotor shaft journalled in said escuteheon plate eccentricallyof said rotor shaft and operatively connected with the latter.

3. In radio apparatus, the combination of a rotative tuning unitincluding a frame, a rotor shaft, and a rotor shaft bearing on one endof said frame, a current control switch mounted on said rotor shaftbearing outside of said frame, a control shaft for said switch extendingcoaxially through said rotor shaft bearing and rotor shaft, andindependent switch and rotor control means both disposed at the oppositeend of said frame.

4. In radio apparatus, the combination of a rotative tuning unitincluding a frame, a rotor shaft and a rotor shaft bearing on one end ofsaid frame, a current control switch mounted on said rotor shaft hearingoutside of said frame including an insulating piece carried by saidbearing and having a pair of oppositely disposed spring contact membersprojecting rearwardly therefrom, and a rotatable switch memberinterposed between said contact members, a control shaft for said switchmember extending coaxially through said rotor shaft bearing and rotorshaft, and independent switch and rotor control means both disposed atthe opposite end of said frame.

Signed at Chicago, 111., this 2nd day of Dec., 1926.

PAUL A. CHAMBERLAIN.

